SNAA393 January   2024 LMK6C , LMK6D , LMK6H , LMK6P

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Why use a Phase Noise Analyzer?
  5. 2Understanding Phase Noise Plots
  6. 3Phase Noise Analyzer Measurement Settings
    1. 3.1 Start or Stop Frequency
    2. 3.2 Averaging and Correlation
    3. 3.3 Persistence
    4. 3.4 Spurious View Modes
    5. 3.5 Other Settings
  7. 4Hardware Setup for Different Clocking Formats
    1. 4.1 LVCMOS
    2. 4.2 LVDS
    3. 4.3 LVPECL/HCSL
    4. 4.4 Balun Recommendations
  8. 5Typical Measurements with Different Termination Schemes
    1. 5.1 LVCMOS
    2. 5.2 LVDS
    3. 5.3 LVPECL
    4. 5.4 HCSL
  9. 6Summary
  10. 7References

3.4 Spurious View Modes

Some PNAs can change how spurs are represented in phase noise plots. Power or Spurs Enabled mode can show the full power of spurs without any filtering. Normalized mode will divide down the spur power by the frequency offset, meaning higher frequency spurs will appear proportionally smaller compared to spurs that are close to the carrier frequency. Omit or Spurs Off mode will remove spurs entirely from the phase noise plot. The following images show a comparison between spurious view modes for a LMK6P 156.25MHz variant.

GUID-20231013-SS0I-KZ7G-318V-QT6HP8CPC5JQ-low.png Figure 3-1 Omit Spur View
GUID-20231013-SS0I-LGG6-HFPT-JV57WTJ7SNDM-low.png Figure 3-2 Normalized Spur view
GUID-20231013-SS0I-2H78-QX9Q-BXMBBP3QSR4G-low.png Figure 3-3 Power Spur View